Cementitious compositions for decreasing the rate of water vapor emissions from concrete and methods for preparing and using the same

ABSTRACT

Cementitious compositions and processes for preparing and using the cementitious compositions are provided. The cementitious compositions are characterized by the property of a reduced or an attenuated water vapor emission of a hardened concrete formed therefrom.

FIELD OF INVENTION

Various embodiments of the present invention relate to cementitiouscompositions used in preparing a concrete having an attenuated rate ofwater vapor emissions after hardening. Various embodiments of theinvention also relate to methods of preparing and using the cementitiouscompositions of the invention. Methods for estimating the amount ofwater vapor emissions that can be expected to occur after hardening of acementitious mix as well as other associated properties of concrete arealso provided, according to certain embodiments.

BACKGROUND OF THE INVENTION

Concrete generally refers to a mixture of natural and/or artificialaggregates, such as, for example, sand and either a gravel or a crushedstone, which is held together by a binder of cementitious paste to forma highly durable building material. The paste is typically made up of ahydraulic cement, such as Portland cement, and water and may alsocontain one or more chemical admixtures as well as supplementarycementing materials, such as, for example, fly ash or ground granulatedblast furnace slag cement.

Early cements were based on calcined lime, which is produced by exposinglimestone at an elevated temperature, for example, a temperature well inexcess of 800° C., in the presence of an oxygen-containing atmosphere toform quick-lime according the reaction in equation (1).

CaCO₃→CaO+CO₂(g)   (1)

Hydraulic limes are derived from calcined limes that have some amount ofclay. The clay provides silicon and aluminum that react with the calciumfrom the limestone to produce cements having complex compounds thathydrate. These compositions even have the ability to harden underwater.Portland cement eventually evolved from these materials.

Most construction cements today are hydraulic, and most of these arebased on Portland cement. Hydraulic cements set and harden after beingcombined with water, as a result of chemical reactions induced by thewater, and demonstrate an improved strength and stability even underwater after hardening.

Setting and hardening of hydraulic cements is caused by hydrationreactions that occur between the compounds that make up the cement andwater, which result in the formation of hydrates or hydrate phases. Thecementitious composition begins to progressively stiffen leading to theonset of setting, where additional consolidation of the hydrationreactants occurs. Hardening follows setting, which is characterized by asteady growth in the compressive strength of the material over a periodthat can range from a few days in the case of “ultra-rapid-hardening”cements to several years in the case of ordinary cements.

Portland cement consists of five major compounds as well as someadditional minor compounds. The major compounds are tricalcium silicate,3CaO.SiO₂; dicalcium silicate, 2CaO.SiO₂; tricalcium aluminate,3CaO.Al₂O₃; tetracalcium aluminoferrite, 4CaO.Al₂O₃.Fe₂O₃; and gypsum,CaSO₄.2H₂O. The hydration of tricalcium silicate is represented by thereaction according to equation (2).

2(3CaO.SiO₂)+11H₂O→3CaO.2SiO₂.8H₂O+3Ca(OH)₂   (2)

Upon the addition of water, the reaction rapidly progresses to releasecalcium and hydroxide ions. Once the water solution becomes saturated,the calcium hydroxide begins to precipitate forming a crystallinestructure. Calcium silicate hydrate is also simultaneously formed. Asthe calcium hydroxide precipitates from solution, the tricalciumsilicate continues to react to form calcium and hydroxide ions. Thereaction is somewhat exothermic involving the evolution of heat as thereaction progresses.

The formation of calcium hydroxide and calcium silicate hydrate provides“seeds” around which calcium silicate hydrate may continue to form. At acertain point, the rate of reaction finally becomes controlled by therate of diffusion of water molecules through the layer of calciumsilicate hydrate that surrounds the unreacted tricalcium silicate, whichprogressively becomes slower as the layer of calcium silicate hydrategrows larger.

Dicalcium silicate is hydrated to form the same products as tricalciumsilicate according to the reaction in equation (3).

2(2CaO.SiO₂)+9H₂O→3CaO.2SiO₂.8H₂O+Ca(OH)₂   (3)

However, the hydration of dicalcium silicate occurs much more slowly andis mildly exothermic in comparison to that for tricalcium silicate.

The reactions of the other major components of Portland cement are morecomplex and beyond the scope of the background discussion given here.However, the hydration of cement experiences five distinct phases. PhaseI is characterized by rapid hydrolysis of the cement compounds and canresult in a temperature increase of several degrees over a period of onthe order of 15 minutes. The evolution of heat begins to dramaticallyslow in phase II, the dormancy period, which can last from one to threehours. In phases III and IV, the concrete begins to harden and theevolution of heat begins to increase due primarily to the continuedhydration of tricalcium silicate. These phases can encompass a period ofup to approximately 32 to 36 hours. Stage V marks a period of continuedhydration, but at much lower rates, and continues as long as unreactedwater and unhydrated silicates remain and can come in contact with oneanother. Stage V typically continues on the order of days, if notlonger.

More commonly, modern-day cements are formulations of hydraulic cementblends. For example, a hydraulic cement, such as, for example, Portlandcement, can comprise up to 75% of ground granulated blast furnace slagthat results in a reduction in early strength but provides increasedsulfate resistance and diminished heat evolution during the stiffeningand hardening stages of the concrete.

Blended hydraulic cements can comprise one or more pozzolan materials,which are siliceous or aluminosiliceous materials that demonstratecementitious properties in the presence of calcium hydroxide. Thesilicates and even aluminates of a pozzolan reacting with the calciumhydroxide of a cement form secondary cementitious phases (e.g., calciumsilicate hydrates having a lower calcium to silicon ratio), whichdemonstrate gradual strengthening properties that usually begin to berealized after 7 days of curing.

A blended hydraulic cement may comprise up to 40% or more fly ash, whichreduces the amount of water that must be blended with the cementitiouscomposition allowing for an improvement in early strength as theconcrete cures. Other examples of pozzolans that can be used inhydraulic cement blends include a highly reactive pozzolan, such as, forexample silica fume and metakaolin, which further increases the rate atwhich the concrete gains strength resulting in a higher strengthconcrete. Current practice permits up to 40 percent or higher reductionin the amount of hydraulic cement used in the concrete mix when replacedwith a combination of pozzolans that do not significantly reduce thefinal compressive strength or other performance characteristics of theresulting concrete.

The cementitious materials in concrete require water, typically known aschemical water or hydration water, to chemically evolve into a hard,crystalline binder. For example, Portland cements generally require upto about 40% of their weight as water in order to promote completehydration and chemical reaction.

Excess water has conventionally been added to make concrete more plasticallowing it to flow into place. This excess water is known as water ofconvenience. A small amount of the water does escape as a result ofsolids settling during the plastic phase, evaporation at the atmosphericinterface, and absorption into accepting interface materials. However,most of the water of convenience remains in the concrete during andimmediately following hardening. The water of convenience can thenescape into the atmosphere following the hardening of the concrete. Thewater of convenience may represent up to about 70% of the total water inthe concrete.

The concrete construction and floor-covering industries may incur bothconstruction delays and remedial costs as a result of water vaporemissions and water intrusion from concrete. For example, adhesives andcoatings used in the construction of concrete floors are relativelyincompatible with moisture that develops at the concrete surface.Moisture may also create an environment for promoting the growth ofmold.

Water tightness in concrete structures is a measure of the ability ofthe hardened concrete to resist the passage of water. Water vaporemission is proportional to the state of relative dryness of the body ofthe concrete structure. Once isolated from external sources of water,water vapor emissions are derived from the amount of water that is usedin excess of that needed to harden the cementitious materials, i.e., thewater of convenience. Depending upon the atmospheric temperature andhumidity at the surface and the thickness of the concrete, theelimination of excess water through water vapor emissions can take onthe order of many months to reach a level that is compatible with theapplication of a coating or an adhesive.

Installation of an impermeable barrier on the surface of the concreteprior to reaching an acceptable level of dryness may result in moistureaccumulation, adhesive failure, and a consequential failure of thebarrier due to delamination. Premature application of coatings andadhesives increases the risk of failure, while the delay caused bywaiting for the concrete to reach an acceptable level of dryness oftenresults in unacceptable construction delays.

The floor covering industry has determined, depending on the type ofadhesive or coating used, that a maximum water vapor emission rate offrom 3 to 5 pounds of water vapor per 1,000 square feet per 24 hourperiod is representative of a state of slab dryness necessary beforeadhesive may be applied to the concrete floor.

There remains a need in the art for cementitious compositions thatreduce the amount of time needed to reach a desired water vapor emissionrate in concrete floors enabling a more timely application of coatingsand adhesives.

It is known in the art that certain polymers classified assuperplasticizers may be included in cement in order to reduce theamount of water of convenience needed to allow the cementitious mix tomore readily flow into place. Certainly, a reduction in the amount ofexcess water remaining after the concrete hardens should lead to areduction in the amount of time necessary to reach a desired water vaporemissions rate. However, the use of superplasticizers alone does notaddress other effects that influence the rate of water vapor emissionfrom the hardened concrete.

There remains a need in the art for cementitious compositions thatfurther reduce the amount of time necessary to reach a desired watervapor emission rate in concrete floors beyond that which is achievedthrough reduction in the amount of water required through the use of asuperplasticizer additive.

BRIEF SUMMARY OF THE INVENTION

Various embodiments of the invention relate to cementitious compositionsthat result in a concrete having a reduced amount of time needed toachieve a desired water vapor emission rate. While not intending to bebound by theory, certain embodiments of cementitious compositions offerthe improvement of providing a hardened concrete that allows for theapplication of coatings and adhesives sooner than concretes produced bycementitious compositions known in the art.

Certain embodiments of the invention provide an inventive analyticalprocedure for quickly estimating various properties of a concrete. Theinventive can be preferred, in certain embodiments, because of its useof smaller quantities of mortar ingredients and a reduced sample sizeover the size of conventional concrete samples.

In one of the various aspects of the invention, a cementitiouscomposition is provided for attenuating a water vapor emission from aconcrete comprising a hydraulic cement; a superplasticizer, preferably apolycarboxylate superplasticizer; and a finely divided material, thefinely divided material having a preferred particle size of less thanabout 75 microns.

In an embodiment of the invention, the finely divided material is acement replacement. Preferably, the cement replacement includeslimestone fines, a ground granulated blast furnace slag, a pozzolan, andany combinations thereof. For example, the pozzolan may comprise anynatural pozzolan; any artificial pozzolan, such as, for example, a flyash; and any combination thereof. In certain embodiments of theinvention, the pozzolan may also comprise a highly reactive pozzolan.

In an embodiment of the invention, the cementitious compositions furthercomprise an aggregate. In certain embodiments of the invention, thecementitious composition has about 25% to about 70% by weight of ahydraulic cement based on the total weight of the cementitiouscomposition; about 0.04% to about 80% by weight of a finely dividedmaterial based on the total weight of the cementitious composition; andabout 4 to about 16 ounces of a superplasticizer per 100 pounds ofcement. In other embodiments, the concentration of superplasticizer isbased upon the total weight of the cementitious composition and may havea concentration from about 4 to about 16 ounces per 100 pounds of thecementitious composition.

The aggregate, in certain embodiments of the invention, may comprise afine aggregate and a coarse aggregate. In a preferred embodiment of theinvention, a ratio by weight of the fine aggregate to the totalaggregate is in a range from about 0.25 to about 1.00.

Any of the cementitious compositions may be combined with an amount ofwater to form a cementitious mix. In certain preferred embodiments ofthe invention, the cementitious mix has a water to cementitious ratio offrom about 0.2 to about 0.4.

An aspect of the invention provides a cementitious mix used forpreparing a concrete or a concrete structure. Generally, thecementitious mix may comprise a hydraulic cement, an aggregate, a cementreplacement, water, and a superplasticizer, preferably a polycarboxylatesuperplasticizer. In preferred embodiments of the invention, thecementitious mix is used to prepare a concrete or a concrete structurehaving an attenuated water vapor emission.

According to certain embodiments of the invention, the cementitious mixcomprises a hydraulic cement having a concentration from about 10 wt %to about 30 wt % based on a total weight of cementitious compounds; anaggregate having a concentration from about 45 wt % to about 65 wt %based on the total weight of cementitious compounds; a densifyingcalcium silicate precursor having a concentration from about 2.5 wt % toabout 25 wt % based on the total weight of cementitious compounds; anamount of water sufficient to provide a water to cementitious ratio offrom about 0.2 to about 0.4; and a polycarboxylate superplasticizerhaving a concentration from about 4 ounces to about 16 ounces per 100pounds of cementitious compounds.

Another aspect of the invention provides a method of preparing acementitious composition comprising the steps of mixing a hydrauliccement with a finely divided material, preferably having a particle sizeof less than about 75 microns; and adding an admixture comprising asuperplasticizer. In a preferred embodiment, the prepared cementitiouscomposition will be used in preparing a concrete having an attenuatedwater vapor emission.

In certain embodiments of the invention, the finely divided materialcomprises a cement replacement, wherein the cement replacement can beany of a pozzolan, a ground granulated blast furnace slag, and anycombination thereof. In various other embodiments of the invention, theratio by weight of the cement replacement to the total weight of thecementitious composition is in a range from about 0.03 to about 0.8.

In another embodiment of the invention, the cement replacement comprisesa calcium carbonate containing material having a concentration of fromabout 0.13 wt % to about 7 wt % based on the total weight of thecementitious composition.

The method of preparing a cementitious composition may additionallycomprise the step of incorporating an aggregate into the cementitiouscomposition.

Another aspect of the invention provides a process of preparing aconcrete structure using a cementitious composition, preferably acementitious composition of the invention, involving the steps ofproviding the cementitious composition comprising a hydraulic cement, afinely divided material having a particle size of less than about 75microns, and a superplasticizer; blending an amount of water into thecementitious composition to prepare a cementitious mix; using thecementitious mix to prepare a perform of the concrete structure; andcuring the cementitious mix to a hardened concrete. In certain preferredembodiments of the invention, the hardened concrete has an attenuatedwater vapor emission.

In a preferred embodiment of the invention, the amount of water used toprepare the cementitious mix is minimized to an amount that issufficient to hydrolyze the cementitious composition and allow theprepared cementitious mix to achieve a desired level of plasticity.

In certain other embodiments of the invention, the method of using acementitious composition additionally comprises the step of applying aregimen for facilitating a more rapid curing of the cementitious mix tothe hardened concrete.

In an embodiment of the invention, the amount of water, a concentrationof the superplasticizer, and a ratio by weight of the finely dividedmaterial to the cement are proportioned to achieve a desired level ofplasticity while achieving a desired property of a hardened concrete.The desired property may be any of minimizing an amount of time neededto achieve a water vapor emission of the hardened concrete, minimizingan amount of time needed to achieve an internal relative humidity of thehardened concrete, a reduced shrinkage of the hardened concrete, amaximum heat of hydration, and any combination thereof.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a graphical illustration of the total small panel water vaporloss of a mortar against the corresponding water vapor loss by 2×2 footpanels of an associated concrete; and

FIG. 2 is a graphical illustration of the water loss from the mortarpans versus the water vapor emissions measured from the concrete panels.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which some, but not allembodiments of the inventions are shown. Preferred embodiments of theinvention may be described, but this invention may, however, be embodiedin many different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Theembodiments of the invention are not to be interpreted in any way aslimiting the various inventions described herein.

Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation. Allterms, including technical and scientific terms, as used herein, havethe same meaning as commonly understood by one of ordinary skill in theart to which this invention belongs unless a term has been otherwisedefined. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningas commonly understood by a person having ordinary skill in the art towhich this invention belongs. It will be further understood that terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and the present disclosure. Suchcommonly used terms will not be interpreted in an idealized or overlyformal sense unless the disclosure herein expressly so definesotherwise.

As used in the specification and in the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contextclearly indicates otherwise. For example, reference to “a concrete”includes a plurality of such concretes.

As used herein, “wt %” or “weight percent” or “percent by weight,”unless specifically stated to the contrary, means a weight percentage ofthe component based on the total weight of the composition or article inwhich the component is included.

The term “attenuated water vapor emission,” as used herein, means acementitious composition that ultimately provides a cementitious mixthat produces a hardened concrete that shows a reduction in the amountof time needed to achieve a desired water vapor emissions rate. In anembodiment of the invention, the desired water vapor emissions rate, forexample, is 3 lb/1000 ft²·24 hr. In certain embodiments of theinvention, the attenuated water vapor emission may be measured based onthe number of days required to achieve a desired internal relativehumidity, for example, a 75% relative humidity.

The term “concrete structure,” as used herein, is intended to be broadlydefined to refer to any structure which is composed in at leastsignificant part of concrete which has cured and hardened. A concretestructure includes, but is not limited to, a bridge, a roadway, aparking lot, a sidewalk, a curb, a parking garage, a floor, a patioslab, a support column, a pier, a marine structure, a piling, a conduitand any other paved surface whether located inside or outside.

As used herein, a “cement replacement” is a compound that partiallysubstitutes for a compound that functions as the primary cementcompound, such as, for example, a hydraulic cement, in a cementitiouscomposition. Without intending to be bound by theory, the cementreplacement itself may have binding properties similar to a cement. Assuch, any compound that can be chemically reacted or hydrolyzed by waterto ultimately form other compounds that promote the hardening of acement may, in certain embodiments, be a cement replacement. In someembodiments of the invention, the cement replacement may demonstratecementitious properties because of their mere presence with anothercomponent of cement in the cementitious composition. A pozzolan is anon-limiting example of cement replacement that demonstratescementitious properties when in the presence of another component ofcement in the cementitious composition.

In certain embodiments of the invention, a cement replacement may bechosen to impart additional properties to the cement. In a non-limitingexample, calcium carbonate may not only function as a cementreplacement, but may also act as any one of a filler, a densifier, anaccelerator of hydration, and any combination thereof. The compositionsof the invention, in certain embodiments, may include these types ofcompounds as well.

As used herein, the term “cementitious composition” refers to acomposition that includes a cement material and, optionally, any of apozzolan, one or more fillers, adjuvants, additives, dispersants, andother aggregates and/or materials that, typically upon being combinedwith water, form a slurry that hardens to a concrete upon curing. Cementmaterials include, but are not limited to, hydraulic cement, gypsum,gypsum compositions, lime and the like.

As used herein, the term “cementitious mix” refers to the final mixturethat comprises the compounds intended to be part of the formulation usedto pour or cast a concrete. In a non-limiting example, the cementitiousmix, in certain embodiments, comprises a cementitious composition andthe desired amount of water.

As used herein, the term “fine calcium carbonate” means a calciumcarbonate having a particle size of less than about 200 microns, lessthan about 150 microns, less than about 100 microns, and, preferably,less than about 75 microns. In certain embodiments of the invention, thefine calcium carbonate is introduced as part of a mixture that includesother compounds, such as, for example, alkaline earth and alkali metalcarbonates. Of course, another source of fine calcium carbonate islimestone, for example, the crushed limestone marketed under thetradename of limestone fines available form Omya, Inc. (Alpharetta,Ga.). Limestone fines are generally understood to be small particulatesof limestone, typically less than 65 mesh, though not intended to belimiting, generated when limestone is crushed or pulverized. In anexemplary embodiment of the invention, the fine calcium carbonate has aparticle size of less than about 75 microns and is filtered from aground mixture comprising calcium carbonate by using a standard sievesize having 75 micron openings or a varying plurality of openings of ±75microns.

The term “pozzolan,” as used herein, refers to a siliceous or siliceousand aluminous material that, by itself, possesses substantially littleor no cementitious value, but when, in particular, in a finely dividedform and in the presence of water, chemically reacts with calciumhydroxide to form compounds possessing cementitious properties.Non-limiting examples of pozzolans include fly ash, silica fume,micronized silica, volcanic ashes, calcined clay, and metakaolin.

As used herein, the term “highly reactive pozzolan” are pozzolans thatreadily react with free lime to form a siliceous binder. Non-limitingexamples of highly reactive pozzolans include silica fume andmetakaolin.

The term “slump,” as used herein when referring to a cementitious mix,means the amount of subsidence of a cementitious composition.Conventionally, slump has been measured by the ASTM C143 (2008 is themost recent specification) standard test procedure, which measures theamount of subsidence of a cementitious composition after removing asupporting cone, as specified in the test procedure.

The term “superplasticizer,” as used herein, is defined as a waterreducer, in particular, a high-range water reducer, or an additive thatreduces the amount of water needed in a cementitious mix while stillmaintaining the workability, fluidity, and/or plasticity of thecementitious mix. Superplasticizers may include, but are not limited toformaldehyde condensates of at least one compound selected from thegroup consisting of methylolation and sulfonation products of each ofnaphthalene, melamine, phenol, urea, and aniline, examples of whichinclude metal naphthalenesulfonate-formaldehyde condensates, metalmelaminesulfonate-formaldehyde condensates, phenolsulfonicacid-formaldehyde condensate, and phenol-sulfanilic acid-formaldehydeco-condensates. Superplasticizers may also include the polymers andcopolymers obtained by polymerizing at least one monomer selected fromthe group consisting of unsaturated monocarboxylic acids and derivativesthereof, and unsaturated dicarboxylic acids and derivatives thereof.Indeed, in preferred embodiments of the invention, the superplasticizercomprises a polycarboxylate superplasticizer.

The term “polycarboxylate superplasticizer” encompasses a homopolymer, acopolymer, and any combination thereof comprising a polycarboxylic towhich other functional groups may be bonded. Preferably these otherfunctional groups are capable of attaching to cement particles and otherfunctional groups for dispersing the attached cement particle within anaqueous environment. Specifically, polycarboxylate superplasticizers arepolymers with a carbon backbone having pendant side chains with thecharacteristic that at least a portion of the side chains are attachedto the carbon backbone through a carboxyl group or an ether group. Anexemplary polycarboxylate superplasticizer is given by Formula (I).

According to Formula (I):

D=a component selected from the group consisting of the structureaccording to Formula II, the structure according to Formula III, andcombinations thereof.

Additionally, according to Formulas (I), (II), and (III):

X═H, CH₃, C₂ to C₆ alkyl, phenyl, substituted phenyl;

Y₁=H, —COOM;

R=H, CH₃;

Y₂=H, —SO₃M, —PO₃M, —COOM, —OR₃, —COOR₃, —CH₂OR₃, —CONHR₃, —CONHC(CH₃)₂,CH₂SO₃M, —COO(CHR₄)_(n)OH where n=2 to 6;

R₁, R₂, R₃, R₅ are each independently —(CH₂CHRO)_(m)R₄ random copolymerof oxyethylene units and oxypropylene units where m=10 to 500 andwherein the amount of oxyethylene in the random copolymer is form about60% to about 100% and the amount of oxypropylene in the random copolymeris from about 0% to about 40%;

R₄═H, methyl, C₂ to C₆ alkyl;

M=alkali metal, alkaline earth metal, ammonia, amine, methyl, C₂ to C₆alkyl;

a=0-0.8;

b=0.2-1.0;

c=0-0.5; and

d=0-0.5.

a, b, c, d, d₁, and d₂ represent the mole fraction of each unit and thesum of a, b, c, and d is 1.0. The sum of d₁ and d₂ must be equal to d.

The term “water to cementitious ratio” is defined as the ratio of themass of the water to the mass of the cementitious materials immediatelypresent in the cementitious mix formed upon mixing a cementitiouscomposition with the desired amount of water. Generally, when thecementitious composition also comprises a pozzolan, the mass of thepozzolan will be added to the mass of the cement in determining thewater to cementitious ratio.

The terms “water vapor emission rate” and “water vapor emission(s),” asused interchangeably herein, refers to amount of water emitted from a1,000 square foot surface area of concrete over a 24 hour period. Thewater vapor emission rate, in an embodiment of the invention, may bemeasured by the test described in ASTM F1869 (2004) entitled the“Standard Test Method for Measuring Moisture Vapor Emission Rate ofConcrete Sub-Floor Using Anhydrous Calcium Chloride.” ASTM F1869measures the vapor emission rate by placing an airtight dome containinga specified weight of calcium chloride over the hardened concrete for adefined period of time.

As used herein, the term “workability” refers to the consistency andfeel of a cementitious mixture or a mortar mixture. The requisiteworkability can vary based on the use of the cementitious and/or themortar mixture. For example, depending on the application, the viscosityof the mixture may vary-e.g., a higher viscosity for applications whererapid flowability is not desired or a lower viscosity where rapidflowability is required, such as when performs are used. Of course, asunderstood in the art, other physical property parameters may alsoaffect the workability of the mixture.

In another embodiment of the invention, the internal concrete moisturecontent may be determined using the procedure developed by the ASTMcommittee F.06, also known as the F2170 (2002) standard entitled“In-Situ Testing of Concrete Relative Humidity,” which is commonly usedin Europe. The F-2170-02 test procedure involves drilling ⅝ inchdiameter holes to a depth equal to 40% of the thickness of the concreteslab. The hole is partially lined with a plastic sleeve that is cappedat the entrance of the hole. The apparatus is allowed to acclimate to anequilibrium level for 72 hours prior to inserting a probe for measuringthe internal relative humidity. The floor covering industry requires theinternal relative humidity reading not to exceed 75% prior toapplication of a flooring adhesive.

In yet other embodiments of the invention, the water vapor emission rateis determined by a process or procedure provided, according to certainembodiments of the invention, for more quickly evaluating the potentialwater vapor emissions from concrete. The process or procedure, otherwiseknown herein as the “mortar method,” comprises a procedure for preparinga representative mortar sample having a water to cementitious ratio thatis consistent with that of the concrete to be proportioned. The preparedsample mixture, in an exemplary embodiment, is cast into a small moldhaving a preferred surface to volume ratio of about 0.67 in⁻¹ (6 inch×6inch panels having a volume of about 54 cubic inches) to simulate thedrying experienced by concrete that is exposed to the atmosphere at onlyone surface. The mortar is cast to a depth, which preferablyapproximates the depth of concrete that is immediately reactive toatmospheric temperature and moisture gradients. In certain embodimentsof the invention, the mortar is cast to a depth of about 1½ inches. Thecast samples of mortar are cured and periodically weighed at measuredintervals in order to determine the amount of daily water loss. Thewater vapor loss is used to estimate the drying rate or some otherproperty of a hardened concrete based upon a correlation. Variousmethods of estimating a water vapor emission rate or an internalrelative humidity of a concrete using this procedure are furtherdisclosed herein.

An aspect of various embodiments of the invention described hereinrelates to a cementitious composition, specifically to a cementitiouscomposition resulting in a concrete having a reduced or an attenuatedrate of water vapor emissions after hardening. The cementitiouscompositions preferably are formulated to include at least onesuperplasticizer. More preferably, the at least one superplasticizercomprises a polycarboxylate superplasticizer.

In other embodiments of the invention, the cementitious compositionadditionally comprises a cement replacement. In other preferredembodiments of the invention, the cement replacement comprises a finelydivided material that comprises a material whose particle size is lessthan about 75 microns. In certain preferred embodiments of theinvention, the finely divided material comprises a finely dividedlimestone or a fine calcium carbonate. In other preferred embodiments ofthe invention, the finely divided material comprises a pozzolan, which,without intending to be limiting, reacts with water and the limereleased from cement hydration to form densifying calcium silicates. Incertain embodiments of the invention, the pozzolan may comprise anynatural pozzolan; any artificial pozzolan, such as, for example, a flyash; and any combination thereof. In yet other embodiments of theinvention, the finely divided material comprises a ground slag,preferably, a ground granulated blast furnace slag.

In various embodiments of the invention, the cementitious compositionscan include compounds or be compounded to demonstrate a number ofadvantageous features. In an embodiment of the invention, thecementitious compositions include compounds or are compounded to reducethe amount of water of convenience. In other embodiments of theinvention, the cementitious compositions include certain compounds andare compounded in such a way so as to augment the effectiveness of asuperplasticizer. In yet other embodiments of the invention, thecementitious compositions increase packing, or decrease intersticialspacing, of an aggregate that has been included in the composition,thereby effectively reducing permeability. In still yet otherembodiments of the invention, the cementitious compositions includecompounds or are compounded such that the cements that are included inthe composition consume much of the water present, preferably in such amanner so as to reduce excessive production of reaction heat.

The inventive cementitious compositions, without intending to be boundby theory, offer improvements over other cementitious compositions knownin the art by providing a hardened concrete that demonstrates areduction in the amount of time needed to achieve a desired water vaporemission rate, otherwise known herein as an “attenuated water vaporemission.” In an embodiment, the cementitious compositions will producea hardened concrete that achieves a water vapor emission rate of 3lb/1000 ft²·24 hr in less than about 50 days; preferably, less thanabout 36 days; more preferably, less than about 28 days; and, even morepreferably, less than about 22 days; and, still even more preferably,less than about 17 days.

In various embodiments of the invention, the cementitious compositionsprovide a reduction in the number of days needed to achieve an internalrelative humidity of 75%. The cementitious compositions, according tocertain embodiments of the invention, will produce a hardened concretethat has a 75% internal relative humidity in less than about 50 days;preferably, less than about 36 days; more preferably, less than about 28days; and, even more preferably, less than about 22 days; and, stilleven more preferably, less than about 17 days.

In certain embodiments of the invention, the cementitious compositionsoffer the improvement of providing a finished concrete that allows theapplication of coatings and adhesives much sooner than concretesproduced by conventional cementitious compositions known in the art.

In a preferred embodiment of the invention, the cementitiouscompositions are used to prepare a concrete structure for a flooringapplication. While not intending to be bound by theory, upon being mixedwith water, the cementitious compositions consume and emit water in sucha manner that little water remains in the hardened concrete to disturbwater-based glues that are affixed to or coated onto the hardenedconcrete, which act as floor coverings.

The inventors have discovered that it is important not only to reducethe need for the amount of excess water to be added to the cementitiouscomposition in preparing a cementitious mix, but to also include certaincompounds in the formulation and to compound the formulation of thecementitious compositions in such a way that excess water is morefavorably and rapidly removed than that which can be achieved byconventional cementitious compositions.

The cementitious compositions according to various embodiments of theinvention are formulated by a proper selection of any combination of abinder and/or filler, including any pozzolan; an adjuvant and/or anadditive; and an aggregate demonstrate an attenuated water vaporemission. Preferably, the cementitious compositions of the variousembodiments of the invention will comprise a superplasticizer, even morepreferably, a polycarboxylate superplasticizer. In a preferredembodiment of the invention, the cementitious composition comprises acement replacement, more preferably, the cement replacement comprises afinely divided material, preferably, the finely divided materialcomprising at least one of a finely divided limestone or a fine calciumcarbonate whose particle size is less than about 75 microns, a finelydivided pozzolan and/or slag whose particle size is less than about 75microns, and a finely divided highly reactive pozzolan whose particlesize is less than about 75 microns.

In an embodiment of the invention, the cementitious composition includesa cement. In certain embodiments of the invention, the cement is anyhydraulic cement. Non-limiting examples of hydraulic cements suitablefor use in certain cementitious compositions include any class ofPortland cement; masonry cement; alumina cement; refractory cement;magnesia cements, such as magnesium phosphate cement and magnesiumpotassium phosphate cement; calcium-based cements, such as calciumaluminate cement, calcium sulfoaluminate cement, and calcium sulfatehemi-hydrate cement; natural cement; hydraulic hydrated lime; anycomplex derivative thereof; and any combination thereof.

Aggregates useful in the inventive cementitious compositions include,but are not limited to, sand, stone, gravel, and any combinationthereof. Aggregates are further classified as coarse aggregates thatinclude, for example, gravel, crushed stone, or iron blast furnace slag,and fine aggregates, which is typically a sand. As non-limitingexamples, stone can include limestone, granite, sandstone, brownstone,river rock, conglomerate, calcite, dolomite, serpentine, travertine,slate, bluestone, gneiss, quarizitic sandstone, quartizite, and anycombination thereof.

Other specialty aggregates include heavyweight aggregates andlightweight aggregates. Heavyweight aggregates can include, but are notlimited to, barite, magnetite, limonite, ilmenite, iron, and steel.

Common lightweight aggregates that are found in certain embodiments ofthe invention include, but are not limited to, slag, fly ash, silica,shale, diatomonous shale, expanded slate, sintered clay, perlite,vermiculite, and cinders. In certain embodiments of the invention,insulating aggregates may also be used. Non-limiting examples ofinsulating aggregates include pumice, perlite, vermiculite, scoria, anddiatomite. In yet other embodiments of the invention, the cementitiouscomposition may additionally comprise any of the aggregates selectedfrom expanded shale, expanded slate, expanded clay, expanded slag, fumedsilica, pelletized aggregate, processed fly ash, tuff, and macrolite. Instill other embodiments of the invention, an aggregate may comprise amasonry aggregate non-limiting examples of which include shale, clay,slate, expanded blast furnace slag, sintered fly ash, coal cinders,pumice, and scoria.

In certain embodiments of the invention, an aggregate may comprise anycombination of coarse aggregates and fine aggregates. Coarse aggregatesare generally considered those aggregate materials retained on a number4 sieve. Fine aggregates are generally considered those aggregatematerials that pass through the number 4 sieve. For example, refer toASTM C33 (2007), which supersedes ASTM C33 (2003), and ASTM C125 (2007),which supersedes ASTM C125 (2002) and ASTM C125 (2000a) standardspecifications for concrete additives for a more comprehensivedescription of how to distinguish between fine aggregates and coarseaggregates.

In an embodiment of the invention, the cementitious compositioncomprises a cement replacement. In an embodiment of the invention, thecementitious composition comprises a cement replacement, the cementreplacement comprising a finely divided material. In an embodiment ofthe invention, the finely divided material comprises a fine calciumcarbonate. In a preferred embodiment of the invention, the fine calciumcarbonate has a particle size of less than about 75 microns. In anembodiment of the invention, the finely divided material compriseslimestone fines, and the cementitious composition has a ratio by weightof finely divided material to the total weight of the cementitiouscomposition of from about 0.01 to about 1.0, from about 0.03 to about0.8, from about 0.05 to about 0.8, from about 0.2 to about 0.8, and fromabout 0.3 to about 0.7. In other embodiments of the invention thecementitious composition has a ratio by weight of finely dividedmaterial to the total weight of the cementitious composition of fromabout 0.05 to about 0.4, and from about 0.1 to about 0.3. In a certainpreferred embodiment of the invention, the cementitious composition hasa ratio by weight of finely divided material to the total weight of thecementitious composition of from about 0.03 to about 0.8.

In an embodiment of the invention, the cement replacement may comprise adensifying precursor. As used herein, the term “precursor” refers to acompound, complex or the like that, after at least one of becomingchemically activated, becoming hydrated, or through at least one otherpreparation step becomes converted into a desired form to serve tofurther densify a concrete. In a preferred embodiment of the invention,the densifying precursor is a densifying calcium silicate precursor.

In an embodiment of the invention, the finely divided material comprisesa pozzolan and/or a slag. In a preferred embodiment of the invention,the pozzolan and/or the slag have a particle size of less than about 75microns. In another preferred embodiment of the invention, the pozzolanand/or slag have a particle size of less than about 45 microns. In anembodiment of the invention, the finely divided material comprises anyof a pozzolan, such as, for example, a fly ash; a hydraulic addition,such as, for example, a ground granulated blast furnace slag; and anycombination thereof, and the cementitious composition has a ratio byweight of finely divided material to total weight of the cementitiouscomposition of from about 0.05 to about 0.8, from about 0.20 to about0.80, and, preferably, from about 0.13 to about 0.75. In anotherembodiment of the invention, the finely divided material comprises ahighly reactive pozzolan and the cementitious composition has a ratio byweight of finely divided material to total weight of the cementitiouscomposition preferably of from about 0.05 to about 0.2, and, morepreferably, from about 0.06 to about 0.10. In certain embodiments of theinvention, the finely divided material comprises a pozzolan selectedfrom the group consisting of any natural pozzolan; any artificialpozzolan, such as, for example, a fly ash; and any combination thereof.

In certain embodiments of the invention, the cementitious compositionincludes an admixture and/or additive including such admixtures oradditives that function as accelerators, shrinkage reducing agentsretarders, thickeners, tracers, air-entraining agents, air detrainingagents, corrosion inhibitors, pigments, wetting agents, antifoamingand/or defoaming agents, any polymer that is water soluble, waterrepellants, fibers, damp proofing agents, gas formers, permeabilityreducers, pumping aids, viscosity control additives, other rheologymodifying additives, fungicidal and/or germicidal agents, insecticidalagents, finely divided mineral admixtures, alkali-reactivity reducers,pH control agents and/or buffers, bonding admixtures, strength enhancingagents, shrinkage reduction agents, water reduction additives, and anymixture thereof.

In an embodiment of the invention, the cementitious compositioncomprises a cement, preferably, a hydraulic cement, having aconcentration from about 10 wt % to about 80 wt %, and from about 25 wt% to about 70 wt % based on the total weight of the cementitiouscomposition. In certain embodiments of the invention, the cementitiouscomposition comprises a cement, preferably, a hydraulic cement, having aconcentration from about 8 wt % to about 35 wt %, from about 10 wt % toabout 30 wt %, from about 12 wt % to about 25 wt %, and from about 14wt% to about 21 wt % based on the total weight of the cementitiouscomposition.

In certain embodiments of the invention, the cementitious compositionmay additionally comprise, at least one of any aggregate, a pozzolan,and any combination thereof.

In an embodiment of the invention, the cementitious compositioncomprises a fine aggregate having a concentration from about 50 wt % toabout 85 wt %, from about 60 wt % to about 80 wt %, and from about 65 wt% to about 75 wt % based on the total weight of the cementitiouscomposition. In another embodiment of the invention, the aggregatecomprises at least one fine aggregate and at least one coarse aggregatehaving a weight ratio of fine aggregate to total aggregate of from about0.25 to about 1.00, from about 0.30 to about 0.75, from about 0.35 toabout 0.65, from about 0.40 to about 0.55, and from about 0.40 to about0.50.

In certain embodiments of the invention, the cementitious compositioncomprises a pozzolan, such as, for example, a fly ash; a groundgranulated blast furnace slag; and any combination thereof having aconcentration from about 5 wt % to about 30 wt %, from about 6 wt % toabout 25 wt %, from about 7 wt % to about 20 wt %, and from about 13 wt% to about 17 wt % based on the total weight of the cementitiouscomposition. In other embodiments of the invention, the cementitiouscomposition comprises a highly reactive pozzolan, such as, for example,metakaolin, silica fume, and the like, including any combinationsthereof, having a concentration from about 0.1 wt % to about 5 wt %, 0.5wt % to about 2.5 wt %, and from about 1.0 wt % to about 2.0 wt % basedon the total weight of the cementitious composition. In certainembodiments of the invention, a material selected from the groupconsisting of a pozzolan, a ground granulated blast furnace slag, andany combination thereof can be a very fine particulate material thatreduces the voidage in the cementitious composition resulting in animproved moisture resistance of the finished concrete.

In certain embodiments of the invention, the cementitious compositioncomprises a fine calcium carbonate having a concentration from about0.03 wt % to about 80 wt %, from about 0.05 wt % to about 25 wt %, fromabout 0.1 wt % to about 15 wt %, and, preferably, from about 0.13 wt %to about 7 wt % based on the total weight of the cementitiouscomposition.

In other embodiments, the inventive cementitious composition comprises adispersant. A non-limiting example of a dispersant includes anypolycarboxylate dispersant, with or without polyether units.Polycarboxylate dispersants include those disclosed in U.S. Pat. Publ.No. 2008/0156225 to Bury, entitled “Rheology Modifying Additive forCementitious Compositions,” fully incorporated herein by reference.Dispersants may additionally include chemicals that function as any oneof a plasticizer, a water reducer, a high range water reducer, afluidizer, an antiflocculating agent, or a superplasticizer. Exemplarysuperplasticizers are disclosed in U.S. Pat. Publ. No. 2008/0087199 toGartner, entitled “Cement Shrinkage Reducing Agent and Method forObtaining Cement Based Articles Having Reduced Shrinkage,” fullyincorporated herein by reference. Dispersants may be selected thatfunction as a superplasticizer.

In an embodiment of the invention, the cementitious composition furthercomprises a superplasticizer. Any superplasticizer disclosed herein orotherwise known in the art may be used in the cementitious compositionsof various embodiments of the invention. In a preferred embodiment ofthe invention, the superplasticizer comprises a polycarboxylateadmixture. A non-limiting example of a commercially availablepolycarboxylate superplasticizer includes GLENIUM® 3000 available fromBASF Corporation. GLENIUM 3000 comprises a polymer with a carbonbackbone having pendant side chains with the characteristic that atleast a portion of the side chains are attached to the carbon backbonethrough a carboxyl group or an ether group. GLENIUM 3000 is a liquid atambient conditions having a specific gravity of approximately 1.08.

For example, using a cementious mix of 658 lb/yd³ of Type III cement,slump of 6 inches, air content of 5-6%, concrete temperature of 65° F.,and curing temperature of 65° F., it has been reported that GLENIUM 3000provides a greater than 2 times increase in compressive strength inconcrete after 8 hours of curing and an improvement of approximately 30%after 12 hours of curing compared to that of a conventionalsuperplasticizer. For a cementitious mix of 658 lb/yd³ of Type I cement,slump of 8-9 inches, non-air-entrained, concrete temperature of 70° F.,dosage of admixtures adjusted to obtain 30% water reduction, GLENIUM3000 has been shown to reduce the initial set time by as much as 2 hoursand 33 minutes compared to that of a conventional superplasticizer.

In an embodiment of the invention, the superplasticizer is in the formof a liquid. In certain embodiments of the invention, the amount ofsuperplasticizer added to the cementitious composition is from about 2ounces to about 30 ounces, from about 4 ounces to about 24 ounces, fromabout 4 ounces to about 20 ounces, and from about 8 ounces to about 20ounces for every 100 pounds of cementitious composition. In certainpreferred embodiments of the invention, the superplasticizer added tothe cementitious composition is from about 4 ounces to about 16 ounces,more preferably about 5 ounces to about 8 ounces, and, even morepreferably, about 8 ounces for every 100 pounds of cementitiouscomposition.

In an embodiment of the invention, the cementitious composition maycomprise a water reducer. A non-limiting example of a water reduceradmixture includes POLYHEED® 997, an ASTM C494 type A water reducer,supplied by BASF Corporation. In certain embodiments of the invention,it is more preferred to use a water reducer with a superplasticizer inorder to achieve a greater reduction in the amount of water mixed withthe cementitious composition.

In an embodiment of the invention, the cementitious composition mayadditionally comprise prepuff particles such as those disclosed in U.S.Pat. Publ. No. 2008/0058446 to Guevare et al., entitled “LightweightConcrete Compositions,” fully incorporated herein by reference. In anexemplary embodiment, the prepuff particles are polymer particles havingan average particle size of at least about 0.2 mm, at least about 0.3mm, at least about 0.5 mm, at least about 0.9 mm, and at least about 1mm up to at most about 8 mm, at most about 6 mm, at most about 5 mm, atmost about 4 mm, at most about 3 mm, and at most about 2.5 mm.

As disclosed herein, the cementitious composition is combined withwater, which functions as chemical water or hydration water and asexcess water that, among other things, serves to plasticize thecementitious mix to render it more flowable. In preferred embodiments ofthe invention, the excess water, otherwise known as water ofconvenience, is minimized. While it is well-known in the art to includeadditives such as a plasticizer, more preferably a superplasticizer, inorder to reduce the amount of water of convenience needed,conventionally, the dependence on excess water has not been entirelyeliminated. For example, conventional cement mixtures tend to have waterto cementitious ratios on the order of 0.4 or higher. Specialtyformulations that include a superplasticizer have been disclosed thatreduce the water to cementitious ratio to 0.25 or higher, for example,similar to those compositions disclosed in U.S. Pat. No. 6,858,074 toAnderson et al., entitled “High Early-Strength CementitiousComposition.”

In certain embodiments, the cementitious compositions are combined withwater having a water to cementitious ratio of less that about 0.5, lessthan about 0.4, less than about 0.35, less than about 0.3, and less thanabout 0.25. In certain embodiments of the invention, the cementitiouscompositions are mixed with water in a water to cementitious ratio ofabout 0.2 or higher. In preferred embodiments of the invention, thecementitious compositions are mixed with water in a water tocementitious ratio of from about 0.2 to about 0.25.

Another aspect of the invention provides methods of preparingcementitious compositions. In a preferred embodiment of the invention, acementitious composition prepared according to certain embodiments ofthe invention is used to further prepare a concrete having an attenuatedwater vapor emission after curing or hardening. In a preferredembodiment of the invention, the cementitious composition isproportioned to achieve rapid drying, which can be measured, forexample, by the ASTM test procedures for vapor emissions or internalrelative humidity, as described herein. In certain other embodiments ofthe invention, the cementitious composition is proportioned to achieve adesired property of a hardened concrete, which preferably can bemeasured using any of the various inventive procedures defined herein.

In an embodiment of the invention, a method for preparing a cementitiouscomposition comprises the steps of mixing a hydraulic cement with acement replacement and adding a superplasticizer. In a preferredembodiment of the invention, the cementitious composition will be usedto form a cementitious mix that produces a concrete having an attenuatedwater vapor emission upon hardening.

In an embodiment of the invention, the cement replacement comprises afinely divided material. In an embodiment of the invention, the finelydivided material has a particle size of less than about 75 microns. Forexample, a finely divided material having a particle size of less thanabout 75 microns may be the material retained on a standard sieve having75 micron openings. Alternatively, a finely divided material having aparticle size of less than about 75 microns may be the material thatpasses through a standard sieve having a varying plurality of openingsof ±75 micron. In another embodiment of the invention, the finelydivided material has a particle size of less than about 45 microns. Inyet another embodiment of the invention, the finely divided materialcomprises a material that passes through a standard sieve size of 200.

In an embodiment of the invention, the finely divided material comprisesa fine calcium carbonate. In another embodiment of the invention thefinely divided material comprises limestone fines, the limestone finescomprising calcium carbonate. Further to this embodiment, thecementitious composition has a ratio by weight of finely dividedmaterial to the total weight of the cementitious composition of fromabout 0.03 to about 0.8, and, alternatively, from about 0.05 to about0.4,.

In another embodiment of the invention, the finely divided material isselected from the group consisting of a pozzolan, such as, for example,a fly ash; a ground granulated blast furnace slag; and any combinationthereof. Further to this embodiment, the cementitious composition has aratio by weight of finely divided material to total weight of thecementitious composition of from about 0.03 to about 0.8, and,alternatively, from about 0.15 to about 0.8.

In still another embodiment of the invention, the finely dividedmaterial comprises a highly reactive pozzolan selected from the groupconsisting of silica fume, metakaolin, and any combination thereof.Further to this embodiment, the cementitious composition has a ratio byweight of finely divided material to cement of from about 0.05 to about0.20.

In certain embodiments of the invention, the cement replacementcomprises a densifying precursor. In a preferred embodiment of theinvention, the densifying precursor is a densifying calcium silicateprecursor.

In an embodiment of the invention, the superplasticizer has aconcentration in a range from about 4 ounces to about 20 ounces forevery 100 pounds of the total weight of the cementitious composition. Ina preferred embodiment of the invention, the superplasticizer includes apolycarboxylate superplasticizer.

In an embodiment of the invention, the method for preparing acementitious composition additionally comprises the step ofincorporating an aggregate in the cementitious composition. In anembodiment of the invention, the aggregate comprises at least one of afine aggregate, a course aggregate, and combinations thereof.

In another embodiment of the invention, a method for preparing acementitious composition comprises the steps of mixing a hydrauliccement with a pozzolan and an aggregate and adding an admixturecomprising a superplasticizer. In a preferred embodiment of theinvention, the cementitious composition will be used to prepare acementitious mix that produces a concrete having an attenuated watervapor emission upon hardening.

Another aspect of the various embodiments of the invention provides acementitious mix comprising any of the cementitious compositions. In acertain embodiments of the invention, the cementitious mix comprises anamount of water sufficient to provide a water to cementitious ratio offrom about 0.05 to about 0.6; from about 0.1 to about 0.5; preferably,from about 0.2 to about 0.4; and, more preferably, from about 0.25 toabout 0.35.

In certain embodiments of the invention, the cementitious mix comprisesa hydraulic cement, an aggregate, a cement replacement, water, and asuperplasticizer. In a preferred embodiment of the invention, the cementreplacement is a densifying calcium silicate precursor. In anotherpreferred embodiment of the invention, the superplasticizer is apolycarboxylate superplasticizer.

According to certain embodiments of the invention, the cementitious mixcomprises a hydraulic cement having a concentration from about 10 wt %to about 30 wt % based on a total weight of cementitious compounds; anaggregate having a concentration from about 25 wt % to about 70 wt %based on the total weight of cementitious compounds; a densifyingcalcium silicate precursor having a concentration from about 3 wt % toabout 80 wt % based on the total weight of cementitious compounds; anamount of water sufficient to provide a water to cementitious ratio offrom about 0.2 to about 0.4; and a polycarboxylate superplasticizerhaving a concentration from about 4 ounces to about 16 ounces per 100pounds of cementitious compounds.

In an exemplary embodiment of the invention, the cementitious mixcomprises a hydraulic cement having a concentration from about 10 wt %to about 30 wt % based on a total weight of cementitious compounds; anaggregate having a concentration from about 25 wt % to about 70 wt %,preferably, from about 45 wt % to about 65 wt % based on the totalweight of cementitious compounds; a densifying calcium silicateprecursor having a concentration from about 3 wt % to about 80 wt %,preferably, from about 5 wt % to about 25 wt % based on the total weightof cementitious compounds; an amount of water sufficient to provide awater to cementitious ratio of from about 0.2 to about 0.4; and apolycarboxylate superplasticizer having a concentration from about 4ounces to about 16 ounces per 100 pounds of cementitious compounds. Inanother embodiment of the invention, the polycarboxylate superplastizerhas a concentration of from about 5 ounces to about 8 ounces per 100pounds of cementitious compounds. In a preferred embodiment of theinvention, the cementitious mix is used to prepare a concrete having anattenuated water vapor emission.

Another aspect of various embodiments of the invention provides methodsof preparing a concrete structure using cementitious compositions toform a hardened concrete having an attenuated water vapor emission uponhardening. In an embodiment of the invention, a particular curingregimen may be applied to poured cementitious mix that allows any excesswater to be more quickly emitted or dissipated as the concrete cures orhardens resulting in a reduced or an attenuated water vapor emissionafter hardening.

In an embodiment of the invention, a method for preparing a concretestructure using a cementitious composition comprises the steps of mixinga hydraulic cement with a cement replacement, adding an admixturecomprising a superplasticizer, and blending an amount of water into thecementitious composition to prepare a cementitious mix. In a preferredembodiment of the invention, the cementitious mix will produce ahardened concrete having an attenuated water vapor emission.

In yet another embodiment of the invention, a method for preparing aconcrete structure using a cementitious composition comprises the stepsof providing the cementitious composition having a hydraulic cement, acement replacement, and a superplasticizer; and blending an amount ofwater into the cementitious composition to prepare a cementitious mix.In a preferred embodiment of the invention, the cementitious mix willproduce a hardened concrete having an attenuated water vapor emission.

Generally, the method of using the cementitious composition additionallycomprises the steps of using the cementitious mix to form a cementitioussegment or a preform of the concrete structure and curing thecementitious segment or preform of the concrete structure to a hardenedconcrete. Further to this embodiment, the cementitious segment may befurther processed. For example, a trowel may be applied to thecementitious segment to, for example, smooth the surface of thecementitious segment and/or to even the distribution of the cementitiousmix in a form.

In certain embodiments, the methods of use may additionally comprise thestep of applying a regime and/or technique that facilitates a more rapidcuring of the cementitious mix to a hardened concrete. Any techniqueknown in the art may be used to more rapidly cure the cementitious mix.Non-limiting examples of such techniques include applying a moisturebarrier between a moisture source and the formed cementitious segment;maintaining the movement of air at the surface of the cementitioussegment being cured to ensure water that evolves from the segment isremoved; heating, for example, with thermal and/or radiant heat, thecementitious segment being cured; and controlling humidity between themoisture barrier and the formed cementitious segment by the maintainingand heating steps.

In an embodiment of the invention, the cement replacement comprises afinely divided material. In certain embodiments of the invention, thefinely divided material has a particle size of less than about 75microns. In an embodiment of the invention, the finely divided materialis a material that passes through a standard sieve size of 200.

In a preferred embodiment, the finely divided material comprises acement replacement. In an embodiment of the invention, the finelydivided material comprises a fine calcium carbonate. In anotherembodiment of the invention the finely divided material compriseslimestone fines, the limestone fines comprising calcium carbonate.Further to this embodiment, the cementitious composition has a ratio byweight of finely divided material to the total weight of thecementitious composition of from about 0.03 to about 0.8, morepreferably, from about 0.07 to about 0.4.

In another embodiment of the invention, the finely divided material isselected from the group consisting of a pozzolan, such as, for example,a fly ash; a ground granulated blast furnace slag; and any combinationthereof. Further to this embodiment, the cementitious composition has aratio by weight of finely divided material to cement of from about 0.15to about 0.8.

In still another embodiment of the invention, the finely dividedmaterial comprises a highly reactive pozzolan selected from the groupconsisting of silica fume, metakaolin, and any combination thereof.Further to this embodiment, the cementitious composition has a ratio byweight of finely divided material to cement of from about 0.06 to about0.105.

In certain embodiments of the invention, the cement replacementcomprises a densifying precursor. In a preferred embodiment of theinvention, the densifying precursor is a densifying calcium silicateprecursor.

In an embodiment of the invention, the superplasticizer has aconcentration in a range from about 4 ounces to about 20 ounces forevery 100 pounds of cementitious composition. In a preferred embodimentof the invention, the superplasticizer at least includes apolycarboxylate superplasticizer.

In a preferred embodiment of the invention, the amount of water blendedinto the cementitious composition is minimized to an amount that issufficient to hydrolyze the cementitious composition and allow theprepared cementitious mix to achieve a desired level of plasticity. Inanother preferred embodiment of the invention, the amount of waterblended into the cementitious composition, the concentration of thesuperplasticizer, and the ratio by weight of the finely divided materialto the cement are proportioned to achieve a desired level of plasticitywhile achieving a desired property of the concrete. In certainembodiments, the desired property of the concrete is any of minimizingan amount of time needed to achieve a water vapor emission of thehardened concrete, minimizing an amount of time needed to achieve aninternal relative humidity of the hardened concrete, a reduced shrinkageof the hardened concrete, and a maximum heat of hydration. Preferably, areduced shrinkage of the concrete will reduce the curling or warping ofthe concrete when used in flooring applications and allow for bettercontrol of joint spacing between concrete segments.

In an embodiment of the invention, the method for preparing acementitious composition additionally comprises the step ofincorporating an aggregate into the cementitious composition. In anembodiment of the invention, the aggregate comprises at least one of afine aggregate, a course aggregate, and any combination thereof.

In another embodiment of the invention, a method for preparing acementitious composition comprises the steps of mixing a hydrauliccement with a pozzolan and an aggregate, adding an admixture comprisinga superplasticizer, and blending an amount of water into thecementitious composition to prepare a cementitious mix. In a preferredembodiment of the invention, the cementitious mix will produce ahardened concrete having an attenuated water vapor emission.

The combination of steps for preparing a cementitious composition foruse in preparing a concrete structure may be varied depending upon thedesired application of the finished concrete structure. For example, inmany circumstances, a concrete structure used in flooring must assurethat a dry substrate be available to which a coating and/or sealant isapplied. While not intending to be limiting, the compositions andmethods of the invention are suitable to such applications because theyprovide a relatively fast drying cementitious mix with an attenuated orreduced water vapor emissions after cure. Typically, the cementitiousmixes for such applications are typically characterized by anappropriate mix of cementitious compounds—i.e., cement(s), slag(s),and/or pozzolans—available to react with the residual water allowing thewater vapor emissions to be reduced to about 3 lb/1000 ft²·24 hr and aninternal relative humidity of about 75% to be achieved in 45 days. Therule-of-thumb for more conventional compositions is 1 month for everyinch of concrete thickness (e.g., 5 months for a commonly used 5 inchconcrete structure).

As disclosed herein, the critical parameters for achieving a relativelyfast drying concrete using the cementitious compositions of theinventions and methods as disclosed herein include water to cementitiousratio, employing a curing technique that is adequate to assure eventualwater impermeability, and the use of a sufficiently fine material tocreate a dense mass.

As further disclosed herein, care must be exercised in blending anypozzolan in order to control the heat of hydration, or else thermalcracking of the concrete could become problematic rendering, for themost part, the use of any pozzolan virtually ineffective. Care must alsobe exercised in proportioning and compounding the cementitious mix. Forexample, a cementitious mix that is too sticky will be difficult to pumpand finish using conventional techniques.

Another aspect of various embodiments of the invention provides atesting protocol or procedure for estimating the amount of water vaporemissions from a concrete after hardening. Preferably, such a protocolrelies upon the use of smaller, more manageable sample panels andprovides results more quickly than waiting for a sample panel of theconcrete to become hardened and achieve a desired water vapor emission.In other embodiments, a testing protocol is provided for determining theinternal relative humidity of the concrete. The inventive testingprotocol may additionally be referred to herein as the mortar method.

In an embodiment of the invention, a method for estimating the watervapor emission from a hardened concrete comprises the steps of preparinga mortar mixture that is representative of the cementitious mix used toprepare the concrete, casting the mortar mixture into a sample;optionally, curing the sample; equilibrating the sample in a chosen orselected environment, calculating a daily weight loss from the sample,and estimating the water vapor emission using an established correlationbased on the daily weight loss of the sample. In certain embodiments,the conditions of the environment are selected to represent the same orsimilar conditions where the concrete structure is to be formed.Exemplary environmental conditions that may be controlled include, butare not limited to, pressure (typically at or near atmosphericpressure), humidity, and temperature.

The steps of the procedure for estimating the water vapor emission ofhardened concrete may also be used to estimate other properties of aconcrete. Such other properties include, but are not limited to, aninternal relative humidity, a required amount of water content of theconcrete, and the required water to cementitious ratio. Of course, thedaily weight loss of the sample will be used to estimate any of theseother properties based upon a correlation that has been established forthese properties.

In an embodiment of the invention, the mortar mixture that isrepresentative of the cementitious mix comprises the compounds presentin the cementitious mix except that the mortar mixture is substantiallyfree of any coarse aggregate. In a preferred embodiment of theinvention, the compounds of the mortar mixture will have the same ratiosas those of the compounds of the cementitious mix.

In an embodiment of the invention, the procedure for preparing a mortarmixture comprises the steps of combining a sufficient amount of thewater with an admix, adding a sand, and continuing to add any remainingwater as the compounds continue to be mixed. In a preferred embodiment,water continues to be added to achieve a target and/or desiredworkability.

In an embodiment of the invention, the sample has a surface to volumeratio of from about 0.4 in⁻¹ to about 1.0 in⁻¹, from about 0.5 in⁻¹ toabout 0.9 in⁻¹, from about 0.6 in⁻¹ to about 0.8 in⁻¹, and, preferably,from about 0.64 in⁻¹ to about 0.7 in⁻¹. In a preferred embodiment of theinvention, the sample is cast to a depth that at least represents thetemperature and/or moisture gradient that develops for a concreteexposed to atmospheric conditions. In a preferred embodiment of theinvention, the depth of the sample is from about 1⅜ inches to about 1⅝inches. In certain embodiments of the invention, the depth of the sampleis greater than about 1⅜ inches, with the depth of the sample greaterthan about 1½ inches being the most preferred.

In an embodiment of the invention, the step of curing the samplecomprises the steps of sealing the sample to prevent water and any othervapor loss and curing the sample for a period of time. In otherembodiments of the invention, the step of curing the sample comprisesthe steps of not sealing the sample for a predetermined period of timeto initially facilitate water and any other vapor loss, subsequentlysealing the sample, and curing the sample for a period of time. Incertain embodiments of the invention, the period of time for curing thesample is at least about 1 day, at least about 2 days, at least about 5days, at least about 7 days, at least about 10 days, at least about 14days, at least about 20 days, at least about 21 days, at least about 25days, and at least about 28 days. Further to this embodiment of theinvention, any curing step that involves sealing the sample additionallycomprises the step of unsealing the sample, preferably, prior to theequilibrating step.

In a preferred embodiment of the invention, any of the methods forestimating water vapor emission from a hardened concrete are performedto at least one of identify one or more compounds to include in thecementitious composition to achieve a desired water vapor emission froma hardened concrete, identify how the compounds of the cementitiouscomposition should be proportioned to achieve a desired water vaporemission from a hardened concrete, identify one or more compounds toinclude in the cementitious mix to achieve a desired water vaporemission from a hardened concrete, identify how the compounds of thecementitious composition should be proportioned to achieve a desiredwater vapor emission from a hardened concrete, and identify anattenuated water vapor emission of a hardened concrete based on any oneof the compound formulation of the cementitious composition, theproportioning of the compounds of the cementitious composition, thecompound formulation of the cementitious mix, the proportioning of thecompounds of the cementitious mix, and any combination thereof. A personwith ordinary skill in the art having the benefit of this disclosureunderstands that the methods, according to various embodiments of theinvention, for estimating water vapor emissions from a hardened concretemay be useful for evaluating any factor, procedure, or parameter thatotherwise may influence the water vapor emission rate of a hardenedconcrete. The mortar method may additionally be applied in comparativetesting of various amounts and types of sands, slags, pozzolans, andcements.

A person having ordinary skill in the art having the benefit of thisdisclosure will recognize the mortar method has several advantages overconventional testing protocols known in the art for determining thewater vapor emission or the internal relative humidity of a hardenedconcrete. For example, the test panels of the mortar method are smallerthan the larger test panels used for the conventional techniques.Additionally, the mortar method offers a much quicker turnaround ofresults over the conventional techniques which typically rely uponwaiting for the full extent of duration of curing and hardening of theconcrete.

The inventive analytical procedure for more quickly estimating dryingrates can be preferred over the ASTM F 1869 calcium chloride test, whichmeasures the amount of water vapor emitted by the concrete in asecondary manner by evaluating the change in chloride weight. Theinventive analytical procedure is also preferred, in certainembodiments, because of its use of smaller quantities of mortaringredients and the samples have a reduced size over conventionalsamples. Many conventional tests operate on much larger concrete panelsthat can weigh up to approximately 250 pounds. The samples of theinventive procedure weight approximately 4 pounds. Without intending tobe bound by theory, the mortar method is preferred, in certainembodiments of the invention, because it creates a technician friendly,easy to use test method to quickly facilitate the determination of watervapor emissions from a hardened concrete mixture.

The mortar method allows the sample specimens to be sized such that thebase mortar quantity is 1/454 of a cubic yard. This allows the weightsof selected compounds to be directly converted to an equivalent amountin gram weight in order to allow convenient laboratory batching.

In an embodiment of the invention, a method for estimating a slump of acementitious mix comprises the steps of portioning a mortar mixture intotwo layers in an ASTM C128 cone, rodding each of the two layers of themortar mixture, leveling the surface of the mortar mixture, lifting thecone free of the mortar, determining a slump of the mortar mixture inincrements of a predefined length, and estimating a slump of acementitious mix, which corresponds to the mortar mix, by dividing thenumber of increments by a conversion factor. In an embodiment of theinvention, the predefined length of an increment is about 1/16 inch. Inan embodiment of the invention, the conversion factor used in the methodfor estimating the slump of cementitious mix is about 4.

In an embodiment of the invention, a method for estimating a volumeyield of a cementitious mix comprises the steps of portioning a mortarmixture into two layers of an ASTM C185 volumetric cylinder, roddingeach of the two layers of the mortar mixture, consolidating each layerof the mortar mixture, leveling the surface of the mortar mixture, andcalculating the volume yield by dividing the net weight of the mortarmixture in the volumetric cylinder into the actual batch weight used toprepare the mortar mixture and multiplying by the volume the mortarmixture occupies in the volumetric cylinder. In an embodiment of theinvention, the method for estimating a volume yield of a cementitiousmix additionally comprises the step of calculating an amount of air inthe mortar mixture by subtracting a volume of the solids from the volumeyield.

In certain preferred embodiments of the invention, any of the methods ofthe invention for estimating the properties of the concrete and/or thecementitious mix are implemented, at least in part, in one or moreanalytical devices for purposes of supporting assessing any of theproperties of a hardened concrete and/or a cementitious composition, asfurther described herein. An exemplary analytical device may comprise atleast one of manually and automatically inputting information needed toperform the estimation into the analytical device, a processing unit forcalculating the estimated property or properties, and an output devicefor providing the results of the estimation procedure. In certainembodiments of the invention, the results of the estimation proceduremay be used to provide recommendations on how to change the compounds inthe formulation or how the compounds of the formulation should beproportioned and/or prepared in order to achieve a more desirableproperty result.

EXAMPLES Example 1

The purpose of the tests in EX. 1 were to determine whether the watervapor emissions from prepared mortar samples determined by the mortarmethod are related to the water vapor emissions from concrete determinedby a conventional test procedure. The tests were conducted on acementitious sample prepared according to the compositions in Table 1.

TABLE 1 Amount Volume Cement 300 g  95.2 cc Slag 500 g 170.0 cc Sand1,500 g 570.3 cc Water 225 g 225.0 cc Admixture 100 oz  5.4 cc

The composition to be used in the mortar method is prepared by placing acement, a portion of the water, and an admixture in the bowl of a Hobart5 quart mixer and mixed at a slow speed for one minute. Sand is addedand mixing is continued at a slow speed for one additional minute. Themixer is stopped and the sides and bottom of the bowl are scraped toinsure that all material is in the mix and has not segregated on theside of the bowl. Mixing is continued at a slow speed for two additionalminutes while gradually adding the remaining water until the desiredconsistency is reached. Mixing continues for an additional 30 secondsafter the last amount of water is added. Total mix time should notexceed 10 minutes.

Portions of the mix are placed in a sand cone, for example, an ASTM C127cone, in two layers, and each layer is rodded 25 times using a ¼ inchrod. The cone top is used to strike the surface level and the cone islifted free of the mortar in 5 seconds. The slump of the mortar ismeasured relative to the original heights in 1/16^(th) inch increments.The number of 1/16^(th) inch increments is divided by 4 to estimate theslump in normally proportioned concrete in inches. (E.g., 20 1/16^(th)inch increments in slump in the mortar equals a potential for 5 inchesof slump in the corresponding concrete.)

A colloid defoamer is used, as needed, to control the flare in mortarair accompanying doses of some admixtures or cements. Without the use ofthis additive, admixture evaluations and cement comparatives may becomedisproportionately influenced by air contents that are atypical of thatproduced in concrete. Typically, it is better to run most comparativeson a same low air basis.

A portion of the mortar is placed in a 400 cc ASTM C1 85 volumetriccylinder in two layers with each layer rodded 25 times using a ¼ inchrod. Each layer is consolidated by rapping the container on the castingsurface several times. The cup is used to strike off the surface level.The volume yield of the mix including air is calculated by dividing thenet weight of the cup mortar into the actual batch weights andmultiplying the result by the 400 cc (the container volume), whichshould also be the volume the mortar mixture occupies in the container.The air content of the mixture may be calculated by subtracting theexpected volume of the solid based upon the gravities of each of thedifferent compounds used in the mixture from the actual volume of themixture. All of the material is placed back into the mixer and remixedfor 30 seconds. The composition is not retempered.

The mortar is placed in the 886 cc mold and consolidated by rapping thefilled mold several times on the casting surface until the mortar islevel and uniform in appearance. The casting is weighed to the nearest0.1 gram on a scale. The cure regimen normally involves sealing aspecimen against water and vapor loss for 7 days; however, otherroutines may be utilized if needed. At the end of the cure cycle, thespecimen is again weighed and placed in an environment where it isallowed to attain equilibrium.

Each specimen is weighed every 24 hours in order to create a water vaporloss record. The results for two panels from four different samples areshown in Table 2.

TABLE 2 Sample 1 Sample 2 Sample 3 Sample 4 Date Test A, gr Test B, grTest A, gr Test B, gr Test A, gr Test B, gr Test A, gr Test B, gr  1-Sep2,013.9 1,945.5 2,027.8 2,180.7 2,012.8 1,987.7 1,635.3 1,844.7 14-Sep1,989.9 1,916.4 2,011.9 2,169.1 1,997.9 1,975.0 1,604.2 1,812.4 19-Sep1,988.1 1,914.4 2,010.2 2,167.8 1,997.1 1,974.3 1,601.2 1,809.5 23-Sep1,987.2 1,913.4 2,009.5 2,167.2 1,997.0 1,974.2 1,599.7 1,807.8 28-Sep1,986.2 1,912.0 2,008.3 2,166.5 1,996.7 1,974.0 1,598.0 1,805.9 Δ Loss27.7 33.5 19.5 14.2 16.1 13.7 37.3 38.8The corresponding sample data for the 2 foot×2 foot panels tested in CCtents, which included the coarse aggregate, are shown in Table 3.

TABLE 3 Sample 4 Sample 1 Sample 2 Sample 3 Vapor Loss, Date Vapor Loss,cc Vapor Loss, cc Vapor Loss, cc cc  1-Sep start start start start 9-Sep 9.1 7.7 6.8 11.3  12-Sep 7.8 6.4 5.8 9.9 16-Sep 7.2 5.8 5.3 9.219-Sep 6.3 5.6 4.9 8.1 22-Sep 6.0 4.5 4.6 7.6 26-Sep 5.8 3.7 4.4 7.229-Sep 5.2 3.9 4.1 7.3  3-Oct 4.7 3.7 3.7 6.3  6-Oct 4.2 3.2 3.1 5.617-Oct 3.9 3.2 3.1 5.2 20-Oct 3.7 3.0 2.9 5.0

FIG. 1 graphically illustrates the total small panel water loss of themortar samples against the corresponding water vapor loss by the 2foot×2 foot sample panels of an associated concrete. The weight loss onthe 6 inch×6 inch×1½ inch sample specimens appear to be directly relatedto the vapor emissions from a 2 foot×2 foot×5 inch concrete sample usingthe same mortar proportions. With additional sample testing, arelationship may be developed that will allow the results from theshorter, small panel tests to be used to estimate the water vaporemissions from the hardened concrete.

Examples 2-3

The purpose of the tests in EX. 2 were to demonstrate the effect of theconcentration of a polycarboxylate superplasticizer and the use of awater reducer on the use of chemically bound water and the extent ofshrinkage realized by the concrete sample mixes of Table 4.

TABLE 4 Sample 5 Sample 6 Sample 7 Compound/Property Concrete MixPortland Cement, Type I-II, lb 800 517 611 Sand, ASTM C33, lb 1,3001,525 1,500 1 inch Stone, ASTM C33, lb 1,850 1,850 1,850 GLENIUM 3000,oz/100 lb cement 16.0 — 8.0 POLYHEED 997, oz/100 lb cement — 5.3 —Water, lb 225 290 228 water to cement ratio 0.28 0.56 0.37 Air Content,% 1.7 3.4 5.4 Density, lb/ft³ (pcf) 155 147 148 Yield, ft³/yd³ 26.9 28.128.1 Slump, inches >6.00 4.25 5.25

The data in Table 5 shows the shrinkage results for the concrete mixesof the examples. The specimens were tested according to the ASTM C157(2006) protocol. Each shrinkage sample was cured at 73° F. and 100%humidity for 24 hours, and followed by a curing step while immersed inwater for 7 days. Drying was conducted at 50% relative humidity and 73°F.

TABLE 5 Sample 5 Sample 6 Sample 7 Days Drying Shrinkage, % 14 0.01330.0193 0.0133 21 0.0203 0.0290 0.0183 28 0.0227 0.0343 0.0217 35 0.02430.0387 0.0230 42 0.0303 0.0487 0.0300 56 0.0350 0.0560 0.0353The cementitious composition of sample 6, which uses a water reducerinstead of a polycarboxylate superplasticizer shows the greatest amountof shrinkage. The cementitious compositions of samples 5 and 7 show thatthe amount of shrinkage can be somewhat maintained with varyingconcentrations of cement in the composition by changing the proportionof superplasticizer to control the water.

The purpose of the test in EX. 3 was to show that the need foradditional water with an increasing concentration of cement in acementitious composition can be offset by increasing the use of asuperplasticizer and also by increasing the concentration of thesuperplasticizer in the cementitious composition. As the sample mixesillustrated in Table 4 show, sample 7 has 94 lbs more concrete thansample 6, and yet has a much smaller demand for water as a result ofusing a superplasticizer versus that of using a water reducer. Sample 5contains 189 lbs more cement than sample 7 and yet has a lower water tocementitious ratio as are result of increasing the concentration ofsuperplasticizer in the cementitious composition.

Example 4

The purpose of the tests in EX. 4 were to demonstrate the effect of apolycarboxylate superplasticizer on the reduction in the amount of timeneeded to achieve a desired rate of water vapor emissions using theconcrete sample mixes of Table 6.

TABLE 6 Sample 8 Sample 9 Sample 10 Compound/Property Concrete MixPortland Cement, Type I-II, lb 800 517 611 Sand, ASTM C33, lb 1,3001,525 1,500 1 inch Stone, ASTM C33, lb 1,850 1,850 1,850 GLENIUM 3000,oz/100 lb cement 16.0 — 8.0 POLYHEED 997, oz/100 lb cement — 5.3 —Water, lb 225 281 228 water to cement ratio 0.28 0.54 0.37 Air Content,% 3.4 N/A 5.6 Density, lb/ft³ (pcf) 155 146 147 Yield, ft³/yd³ 27.0 28.228.2 Slump, inches >6.00 4.50 5.00

The curing data and number of days required to achieve a water vaporemission rate of 3 lb/1000 ft²·24 hr shown in Table 7 were obtained bycasting each of the samples in a 2 foot×2 foot×5½ inch deep panel linedwith polyethylene. Immediately prior to initial set, each panel wasgiven a steel trowel finish and sealed for the noted cure period at 73°F. Following the cure period, the concrete slabs were unsealed andallowed to dry at 50% relative humidity and 73° F. in a drying room. Thewater vapor emissions data was obtained by averaging two calciumchloride dome tests conducted according to the ASTM F1869 test standard.

TABLE 7 Sample 8 Sample 9 Sample 10 Curing Time, days 28 28 28 DryingTime needed for 17 >50 22 3 lb/1000 ft²·24 hr Emissions, daysThe mixture of sample 9 has a water to cementitious ratio that isgreater than that of samples 8 and 10; however, the sample requiresgreater than 50 days drying in order to achieve a water vapor emissionsrate of 3 lb/1000 ft²·24 hr. The mix of sample 7 shows asuperplasticizer helps to attenuate the water vapor emissions over thatof the water reducer used in the mix of sample 9. Sample 8 shows thatincreasing the concentration of the superplasticizer further reduces theamount of drying time needed to achieve the desired water vaporemissions rate.

Example 5

The purpose of the tests in EX. 5 were to demonstrate the effect of apolycarboxylate superplasticizer along with the presence of a reactivepozzolan on the amount of time needed to reduce the internal relativehumidity to a desired value using the concrete sample mixes of Table 8.

TABLE 8 Sample 11 Sample 12 Sample 13 Compound/Property Concrete MixHanson Cement, Type I-II, lb 517 740 740 Silica Fume, lb — 60 —Metakaolin, lb — — 60 Sand, ASTM C33, lb 1,525 1,200 1,200 Sand, ASTMC33 #67, lb 1,950 1,950 1,950 GLENIUM 3000, oz/100 lb cement — 16.2 16.2POLYHEED 997, oz/100 lb cement 5.0 — — Colloid Defoamer, oz 0.5 0.5 0.5Water, lb 264 186 197 water to cement ratio 0.51 0.23 0.25 MixTemperature, ° F. 65 66 67 Air Content, % 1.3 3.6 1.1 Density, lb/ft³(pcf) 152 156 156 Yield, ft³/yd³ 28.1 26.5 26.7 Slump, inches 5.75flowing flowing

Each sample was cast in a 2 foot×2 foot×5½ inch deep panel lined withpolyethylene. Immediately prior to initial set, each panel was given asteel trowel finish and sealed for a 13-day cure period at 73° F.Following the cure period, the concrete slabs were unsealed and allowedto dry at 50% relative humidity and 73° F. in a drying room. Therelative humidity was obtained according to the ASTM F 2170 testprocedure using in situ probes. The curing data and number of daysrequired to achieve an internal relative humidity of 75% for the curedconcrete samples are shown in Table 9.

TABLE 9 Sample 11 Sample 12 Sample 13 Curing Time, days 13 13 13 DryingTime needed to Achieve >63 28 28 75% Relative Humidity, daysThe cementitious composition of sample 11, which used only the waterreducer, produced a concrete having an internal relative humidity of87.3% at the end of 63 days. Samples 12 and 13 comprising silica fumeand metakaolin, respectively, as well as a superplasticizer produced aconcrete that required only 28 days of drying time to achieve aninternal relative humidity of 75%.

Example 6

The purpose of the tests in EX. 6 were to demonstrate the effect ofpartial substitution with a finely divided material (finely dividedlimestone) generally smaller than a U.S. standard sieve size 200. Thesieve produced a finely divided material having a particle size of lessthan about 75 microns. #3 limestone fines represent a finely dividedreactive material, the ASTM C33 sand is a fine aggregate, and theCupertino lime is a coarse aggregate. Samples 14, 15, and 16 of Table 10also include a superplasticizer.

TABLE 10 Sample 14 Sample 15 Sample 16 Sample 17 Compound/PropertyConcrete Mix Cement, lb 500 500  800  500 #3 Limestone Fines, lb — 270 — — Sand, ASTM C33, lb 1,700 1,510   1,450   1,470 Cupertino Lime, St.1,800 1,800   1,800   1,800 ¾, lb GLENIUM 3000, 16 16 16 — oz/100 lbcement POLYHEED 997, — — — 5 oz/100 lb cement Water, lb 213 172  200 269 water to cement ratio 0.43    0.34    0.25 0.54 Mix Time, min 20 1714 10 Mix Temperature, ° F. 82 86 89 88 Density, lb/ft³ (pcf) 153 157 157  150 Yield, ft³/yd³ 27.5   27.1   27.1 26.9 Slump (Spread), inches 5(24) (27) 5¼

The number of days required to achieve a water vapor emission rate of 3lb/1000 ft²·24 hr for the cementitious mixes shown in Table 10 wereobtained by casting each of the samples in a 2 foot×2 foot×5½ inch deeppanel lined with polyethylene. The plates, not subjected to a sealedcure time, were allowed to dry at 50% relative humidity and 73° F. in adrying room. The water vapor emissions data were obtained by using thecalcium chloride dome tests according to the ASTM F1869 test standard.The results are shown in Table 11.

TABLE 11 Sample 14 Sample 15 Sample 16 Sample 17 Drying Time neededfor >53 36 36 >53 3 lb/1000 ft² · 24 hr Emissions, daysAs this data shows, the addition of a finely divided calcium carbonateenables the amount of excess water to be further reduced.

Example 7

The purpose of the tests in EX. 7 were to demonstrate the effect ofpartial substitution with a finely divided material (finely dividedground granulated blast furnace slag and finely divided type F fly ash)generally smaller than a U.S. standard sieve size 200 or particleshaving a size less than about 75 microns along with a superplasticizerin the cementitious compositions using the sample mixes of Table 12.

TABLE 12 Sample 18 Sample 19 Sample 20 Sample 21 Sample 22Compound/Property Concrete Mix Cement, lb 800 600 400 560 680 GroundSlag, lb — 200 400 — — Fly Ash-Type F, lb — — — 240 120 Sand, lb 1,3001,300 1,300 1,300 1,300 GLENIUM 3000, oz/100 lb cement 8 8 8 8 8 Water,lb 195 190 190 210 198 water to cement ratio 0.24 0.24 0.24 0.26 0.25Density, lb/ft³ (pcf) 151 150 149 144 148 Yield, cc³ 950 957 960 1006971 Slump (Spread), inches flowing flowing flowing flowing flowing

The sample mixes were analyzed using the mortar method, as furtherdisclosed herein. Mortar of the same workability level as the concreteof the investigation was mixed and cast in 6 inch×6 inch plastic pans toa depth of 1⅝ inches. The samples were cured unsealed for 24 hours andthen sealed for a 14-day cure. Vapor loss measurements were determinedbased on the changes in weight of the samples and is reported in Table13.

TABLE 13 Sample 18 Sample19 Sample20 Sample 21 Sample 22 Total Water 3.72.9 4.4 7.4 5.6 Vapor Loss, grIncreasing the amount of ground granulated blast furnace slag, as shownin samples 19 and 20, resulted in the same water to cementitious ratioand produced a vapor loss in the same range as sample 18, the controlmix. Substitution of type F fly ash in samples 21 and 22 resulted inprogressively higher vapor emissions over the curing period, butrepresent rates that still are within a satisfactory range.

Example 8

The sample mixes of Table 14 were used to generate a correlation betweenthe water losses measured from the 6 inch×6 inch mortar samples pans andthe water vapor emissions using the 2 foot×2 foot concrete panels.

TABLE 14 Sample Sample Sample Sample Sample Sample 23 24 25 26 27 28Portland Cement, gr 520 520 520 520 650 650 Sand, gr 1,540 1,540 1,5401,540 1,430 1,430 Glenium 3000, oz/100 lb cement 0 4 8 16 0 4 Water, gr285 268 228 205 289 238 water to cement ratio 0.55 0.52 0.44 0.39 0.440.37 Density, lb/ft³ (pct) 138 139 145 146 141 144 Yield, cc³ 1057 1046988 971 1030 1006 Slump, inches 5 5¼ flowing flowing 5 flowing VaporLoss, gr 29.7 23.4 11.8 9.9 17.3 9.7 Sample Sample Sample Sample SampleSample 29 30 31 32 33 34 Portland Cement, gr 650 650 780 780 780 780Sand, gr 1,430 1,430 1,315 1,315 1,315 1,315 Glenium 3000, oz/100 lbcement 8 16 0 4 8 16 Water, gr 220 195 300 282 218 187 water to cementratio 0.34 0.30 0.38 0.36 0.28 0.24 Density, lb/ft³ (pct) 146 149 142144 148 142 Yield, cc³ 984 955 1050 991 978 942 Slump, inches flowingflowing 4¾ 4½ flowing flowing Vapor Loss, gr 6.3 4.6 13.6 8.2 4.1 2.6FIG. 2 is a graphical illustration of the water loss from the mortarpans versus the water vapor emissions measured from the concrete panels.

Example 9

The sample mixes of Table 15 were used to analyze the variations inwater loss measured from the 6 inch×6 inch mortar samples pans for mixescomprising cements and sands from five different regions.

TABLE 15 Sample Sample Sample Sample Sample Sample Sample Sample Sample35 36 37 38 39 40 41 42 43 Cement, gr Permanente, CA 650 — — — — — — — —Maryland — 650 — — — 650 — — — Texas — — 650 — — — 650 — — Michigan — —— 650 — — — 650 — Tennessee — — — — 650 — — — 650 Sand, gr Seacheldt1,430 1,430 1,430 1,430 1,430 — — — — Maryland — — — — — 1,430 — — —Texas — — — — — — 1,430 — — Michigan — — — — — — — 1,430 — Tennessee — —— — — — — — 1,430 Glenium 3000, oz/100 lb 16 16 16 16 16 35 16 16 16cement Water, gr 190 208 208 216 210 224 204 216 206 water to cementratio 0.29 0.32 0.32 0.33 0.32 0.34 0.32 0.33 0.32 Density, lb/ft³ (pcf)149 148 148 146 147 144 148 146 149 Yield, cc³ 953 968 967 985 976 1003970 988 960 Slump, inches 8.0 6.3 6.0 5.5 5.5 5.0 8.0 5.5 7.3 MixTemperature, ° F. 75.0 76.0 75.0 76.0 75.0 75.0 76.0 75.0 75.0 VaporLoss, gr 8.0 6.3 6.0 5.5 5.5 5.0 8.0 5.5 7.3The average vapor loss for these samples was 6.34, while the standarddeviation for the sample was 1.08.

All publications mentioned herein, including patents, patentapplications, and journal articles are incorporated herein by referencein their entireties including the references cited therein, which arealso incorporated herein by reference. The publications discussed hereinare provided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present invention is not entitled to antedate such publicationby virtue of prior invention. Neither should the citation of documentsherein be construed as an admission that the cited documents areconsidered material to the patentability of the claims of the variousembodiments of the invention. Further, the dates of publication providedmay be different from the actual publication dates which may need to beindependently confirmed.

Many modifications and other embodiments of the invention set forthherein will come to mind to one skilled in the art to which thisinvention pertains having the benefit of the teachings presented in thedescriptions herein and the associated drawings. For example, thoughvarious methods are disclosed herein, one skilled in the art willappreciate that various other methods now know or conceived in the artwill be applied to a subject in conjunction with the methods oftreatments or therapies disclosed herein. Therefore, it is to beunderstood that the invention is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.

1. A cementitious composition for attenuating a water vapor emissionfrom a concrete comprising: a hydraulic cement; a superplasticizer; anda finely divided material having a particle size of less than about 75microns.
 2. The cementitious composition according to claim 1, whereinthe finely divided material is a cement replacement.
 3. The cementitiouscomposition according to claim 2, wherein the finely divided materialcomprises limestone fines.
 4. The cementitious composition according toclaim 2, wherein the finely divided material is selected from the groupconsisting of a pozzolan, a ground granulated blast furnace slag, andany combination thereof.
 5. The cementitious composition according toclaim 4, wherein the pozzolan comprises a fly ash.
 6. The cementitiouscomposition according to claim 4, wherein the pozzolan comprises ahighly reactive pozzolan.
 7. The cementitious composition according toclaim 1, wherein the superplasticizer is a polycarboxylatesuperplasticizer.
 8. The cementitious composition according to claim 1,further comprising an aggregate.
 9. The cementitious compositionaccording to claim 8, wherein: the hydraulic cement having aconcentration in a range from about 25% to about 70% by weight based onthe total weight of the cementitious composition; the finely dividedmaterial having a concentration in a range from about 3% to about 80% byweight based on the total weight of the cementitious composition; andthe superplasticizer having a concentration in a range from about 4 toabout 16 ounces per 100 pounds of the cementitious composition.
 10. Thecementitious composition according to claim 8, wherein the aggregatecomprises a fine aggregate and a coarse aggregate.
 11. The cementitiouscomposition according to claim 10, wherein a ratio by weight of the fineaggregate to the total aggregate is from about 0.25 to about 1.00.
 12. Acementitious mix comprising the cementitious composition of claim 1 andan amount of water sufficient to provide a water to cementitious ratioof from about 0.2 to about 0.4.
 13. A cementitious mix comprising: ahydraulic cement having a concentration from about 10% to about 30% byweight based on a total weight of cementitious compounds; an aggregatehaving a concentration from about 45% to about 65% by weight based onthe total weight of cementitious compounds; a densifying calciumsilicate precursor having a concentration from about 2.5% to about 25%by weight based on the total weight of cementitious compounds; an amountof water sufficient to provide a water to cementitious ratio of fromabout 0.2 to about 0.4; and a polycarboxylate superplasticizer having aconcentration from about 4 ounces to about 16 ounces per 100 pounds ofcementitious compounds, wherein the cementitious mix is used to preparea concrete having an attenuated water vapor emission.
 14. A method ofpreparing a cementitious composition comprising the steps of: mixing ahydraulic cement with a finely divided material having a particle sizeof less than about 75 microns; and adding a superplasticizer, whereinthe cementitious composition is used to prepare a concrete having anattenuated water vapor emission.
 15. The method according to claim 14,wherein the finely divided material comprises a cement replacement, thecement replacement selected from the group consisting of a pozzolan, aground granulated blast furnace slag, and any combination thereof. 16.The method according to claim 15, wherein a ratio by weight of thecement replacement to the total weight of the cementitious compositionis in a range from about 0.03 to about 0.8.
 17. The method according toclaim 14, wherein the finely divided material comprises a cementreplacement, the cement replacement comprises a calcium carbonatecontaining material having a concentration of from about 0.13% to about7% by weight based on the total weight of the cementitious composition.18. The method according to claim 14, additionally comprising the stepof incorporating an aggregate in the cementitious composition.
 19. Amethod of preparing a concrete structure using a cementitiouscomposition comprising the steps of: providing the cementitiouscomposition comprising a hydraulic cement, a finely divided materialhaving a particle size of less than about 75 microns, and asuperplasticizer; blending an amount of water into the cementitiouscomposition to prepare a cementitious mix; using the cementitious mix topreform the concrete structure; and curing the preformed cementitiousmix to a hardened concrete, wherein the hardened concrete has anattenuated water vapor emission.
 20. The method according to claim 19,additionally comprising the step of applying a regimen for facilitatinga more rapid curing of the cementitious mix to the hardened concrete.21. The method according to claim 19, wherein the amount of water isminimized to an amount that is sufficient to hydrolyze the cementitiouscomposition and allow the prepared cementitious mix to achieve a desiredlevel of plasticity
 22. The method according to claim 19, the amount ofwater, a concentration of the superplasticizer, and a ratio by weight ofthe finely divided material to the cement are proportioned to achieve adesired level of plasticity while achieving a desired property of ahardened concrete.
 23. The method according to claim 22, the desiredproperty is selected from the group consisting of minimizing an amountof time needed to achieve a water vapor emission of the hardenedconcrete, minimizing an amount of time needed to achieve an internalrelative humidity of the hardened concrete, a reduced shrinkage of thehardened concrete, a maximum heat of hydration, and any combinationthereof.